They are a strange and hectic breed, the political books rushed out within months of any election or leadership contest. They're not classically political biographies, since they lack the time or emotional distance to take the long view of a life and its place in history. But they are rather more than the cheap'n'cheerless "inside stories" knocked out by publishers after, say, a big murder trial or particularly controversial series of Big Brother.

The likes of Mehdi Hassan and James Macintyre's recent primer on Ed Milband, or David Laws's intimate account of the coalition's birth, or even this new life of Nick Clegg (all from Biteback Publishing, master of the speeded-up genre) actually occupy a valuable niche. In an era of shortened news cycles and flickering attention spans, where newspapers only rarely allow reporters real time to explore a subject, it's in books that long-form journalism now flourishes. At their best, these books are a grippingly immediate first draft of history, but at worst, they're literary Pot Noodles, slurries of indigestible facts.

There was a good case for a life of Nick Clegg, who has been revealed by events to be both an unusually ordinary and simultaneously extraordinary politician. He shares with David Cameron and Tony Blair the priceless political gift of normality: the affable, approachable air of a model son-in-law, combined with the knack of expressing complex ideas simply. But that vertiginous career arc – party leader within three years of becoming an MP, national pin-up by the election, pantomime villain within weeks of it – suggests something extraordinary, too. Nice boys rarely end up playing two party leaders off one another to become the first Liberal (Democrat) leader since Lloyd George inside Downing Street.

Chris Bowers's account captures the defiantly normal Clegg, the conscientious head prefect, but the extraordinariness remains elusive. As Bowers says, there is something highly unusual about Clegg, but by the end we are still a long way from knowing what that is.

That Clegg comes from a formidable family is clear: he is descended from two redoubtable women (three, counting the Russian great-great-aunt who may or may not have been a spy) and married to another. His Dutch mother grew up in Indonesia, where she and his grandmother only just survived wartime internment by the Japanese. But the family legacy of brutal times seems to have been not bitterness but a strong liberal belief in tolerance, freedom of thought and the civilising power of education. The very blandness of Clegg's home counties childhood – prep school, music lessons, guinea pigs – must have felt to his elders like a triumph over so much harrowing history.

But beyond that, things are less clear. Is Clegg an ordinary guy who got lucky (first via a televised debate, second when the Tories failed to win the election) and whose luck ran out? Or, as one suspects, but this book doesn't quite prove, is there something more?

In one of the sharper insights, Paddy Ashdown describes being impressed by the young Clegg's "room to grow", a sense of something more always in reserve. Yet there's a sense that this reserve is sometimes not deployed when it should be. There are two mirror incidents recorded here that suggest a hesitancy, a lack of strategic nous, unusual in a senior politician.

The first is Clegg's failure to realise Chris Huhne would go for the leadership when Charles Kennedy resigned in 2007, despite a somewhat vague gentlemen's agreement among a group of young pretenders not to run. Clegg felt bound by it; his rival didn't.

It was a misreading of Huhne's ambition (and perhaps also of the ability of Menzies Campbell, whom the group backed instead) that nearly cost him dear. Huhne lost, but the experience of running a campaign proved useful when the leadership fell vacant again shortly afterwards. This time Clegg ran, but campaigned somewhat scrappily, winning by an uncomfortably narrow margin.

He was, of course, inexperienced then, and if being slightly too honourable is a flaw in politics, it's a likable one. But Clegg seems to have made a very similar mistake during this spring's referendum on electoral reform. When Cameron backtracked on another vague gentlemen's agreement that neither man should personally intervene in the campaign, again Clegg appeared surprised. He seems ill-prepared for ruthlessness, which is risky in politics.

Sadly, Bowers does not draw the parallels between such incidents. And that's the problem with this book: the connective tissue is missing. Bowers has carefully assembled a lot of anecdotes, from a lot of interviews, but not quite pulled them into an insightful narrative. Given a little more time and editing, this book could have been more than the sum of its parts.

But the real timing problem is that Clegg's future is now unmistakably more interesting than his past. While great long-form journalism can predict the former by understanding the latter, this book doesn't quite pull off that trick either; all we're told in the end is that Nick Clegg might still go on to greatness, or he might not. Extraordinary or ordinary after all? We are yet to find out.